Highly sensitive photoalignment of liquid crystals (LCs) can be realized by the polarization preserved triplet energy transfer from doped sensitizers to cinnamate side chains of a photocrosslinkable polymer. Linearly polarized irradiation of sensitizer-doped polymer films with light for selective excitation of the triplet photosensitizer gives rise to azimuthal photodichroism of cinnamates as a result of nanometric triplet energy transfer process preserving the polarization state of triplet-excited photosensitizer. This phenomenon is applicable to the surface-assisted orientational photocontrol of nematic LCs with high performance of extremely low exposure energies.
REFERENCES
Michler’s Ketone was used as a triplet photosensitizer, because its triplet energy is close to that of -cinnamate derivative .